Oracle Data Dictionary

There's a view of all the data dictionary views in oracle called DICTIONARY. So you can query it like so:

select 

 TABLE_NAME,

 COMMENTS 

from 

 DICTIONARY 

order by 

 TABLE_NAME;

This includes comments about most of the views which is really handly. Almost all the views use plurals (ALL_TABLES not ALL_TABLE)

To find all the tables associated with a schema, query ALL_TABLES and specify the appropriate OWNER e.g. SYSADM.